Process for obtaining halogenated diphenols

ABSTRACT

An improved process for obtaining halogenated diphenols which can be pure dihalodiphenols or predetermined, statistical mixtures comprising unreacted diphenol, monohalodiphenols and dihalodiphenols.

This is a division of application Ser. No.58,000, filed July 16, 1979,which in turn, is a division of application Ser. No. 882,242 filed Feb.28, 1978 now U.S. Pat. No. 4,210,765.

This invention relates to an improved process for obtaining halogenateddiphenols. More particularly, this invention relates to an improvedprocess that permits the reaction to be closely controlled enabling puredihalodiphenols or predetermined, statistical mixtures of halogenateddiphenols to be obtained.

BACKGROUND OF THE INVENTION

It is known to prepare halogenated diphenols which can be used asanti-mildew agents, fungicides, fire retardant agents in variouspolyesters, monomers for the preparation of aromatic polycarbonates, andthe like.

The preparation of halophenols, including halodiphenols, halodriphenols,halotetraphenols, etc., is often desired to improve the properties ofthe parent phenol. For instance, the halogenated phenols often possessenhanced, desirable biological properties, compared with nonhalogenatedphenols and have been manufactured on a large scale. For example,pentachlorophenol is a potent wood preservative, pentabromophenol is acomponent of flame retardant formulations,2,2'-methylenebis(3,4,6-trichlorophenol) is a potent and usefulbactericide, and 4,4'-isopropylidenebis(2-chlorophenol) has been used asan anti-mildew agent. Often, derivatives of halophenols are also usefulsuch as polymers derived from 4,4'-isopropylidenebis(2,6-dibromophenol)and the corresponding bis(dichlorophenol) which, in the form ofpolyesters and polycarbonates, possess outstanding flame-retardantcharacteristics as is known in the prior art.

The preparation of halophenols is customarily carried out by directhalogenation with elemental chlorine and/or bromine. In the case ofsimple or stable molecules, this appears to be the simplest process.However, when it is applied to more complicated and sensitivestructures, it often yields by-products that can seriously interferewith the intended end-use of the halophenols. For instance, U.S. Pat.No. 3,062,781 discloses halogenated diphenols which are obtained by adirect halogenation procedure which require further treatment withsodium hydroxide and triethylamine at 80° C. before they can beconverted to polycarbonates of acceptable stability. Such a treatment isnecessary in order to remove aliphatically bound halogens formed in thehalogenation process. It has been found that these aliphatically boundhalogen compounds, which are generally recognizable by their red color,are formed by the cleavage reaction exerted by the hydrogen halidecoproduct on the diphenol. For example, when 4,4'-isopropylidenediphenol(BPA) is employed, the chlorination reaction produces an equimolaramount of hydrogen chloride coproduct as shown below: ##STR1## The HClcoproduct produced in (I) above effects a cleavage reaction on BPA orits chlorinated derivatives as shown below: ##STR2## Thus, thechloroisopropylphenols cause the discoloration and the chlorinatedphenols also have a disagreeable odor. The formation of by-products iseven more pronounced in bromination processes.

German Pat. No. P25 20 317.2 discloses two methods for brominatingand/or chlorinating bisphenols; namely, a gas-solid phase method and asuspension method. From these methods, there are obtained a mixture ofunreacted bisphenol and statistical mixtures of halogenated bisphenolswhich are used to prepare polycarbonates having improved fire retardantproperties.

In the suspension method disclosed in this German patent, the bisphenolis suspended in a halogen-containing hydrocarbon to produce ahalogenated bisphenol. The halogen-containing hydrocarbons disclosed arecarbon tetrachloride and tetrachloroethane, carbon tetrachloride beingpreferred.

While the suspension method disclosed in the above-identified Germanpatent is of interest, it is not entirely satisfactory. For example,since bisphenols are not very soluble in either carbon tetrachloride ortetrachloroethane, excess halogen, i.e., either bromine and/or chlorine,must be used to assure halogenation of the bisphenols. As a result, asignificant amount of halogen is lost in the system during the reactionand the rate of halogenation cannot be closely controlled. Thus, thismethod produces an excess of unreacted bisphenols and, primarily, tri-and tetrahalogenated bisphenols which, when further processed to producea polycarbonate, do not impart good impact properties to thepolycarbonate. Furthermore, the halogenated bisphenols must be isolatedfrom the solvent system before they can be subjected to polymerizationto obtain polycarbonates.

Co-pending application Ser. No. 882,192, filed Feb. 28, 1978 andassigned to the same assignee as this case discloses a continuousprocess for producing high molecular weight polycarbonates includinghalogenating diphenols wherein the diphenol is dissolved or suspended ina solvent system comprising methylene chloride and water and metering ahalogen gas into the solvent system. In that process, water is used toreact with the hydrogen halide produced and thereby minimize theformation of undesirable by-products.

Co-pending application Ser. No. 882,191, filed Feb. 28, 1978, alsoassigned to the same assignee as this case, discloses a process forhalogenating diphenols wherein the diphenol is dissolved or suspended inmethylene chloride and then contacted with a halide while the reactionis concurrently purged with an inert gas. The inert gas serves to sweepout the hydrogen halide produced during the reaction thereby minimizingthe formation of undesirable by-products.

SUMMARY OF THE INVENTION

It has now been found that halogenated diphenols obtainable in highpurity can be prepared by suspending or dissolving the diphenol in asuitable solvent such as methylene chloride and thereafter reacting thediphenol with sulfuryl chloride. Other halogens such as bromine can alsobe concurrently introduced into the reaction system to provide a mixtureof halogens and thereby obtain a halogenated diphenol having apredetermined degree of halogen content and containing a negligibleamount of deleterious by-products. Since this process results inminimizing impurities as well as minimizing the formation of undesirableby-products, the highly pure halogenated diphenol obtained need not betreated further before being used. These halogenated diphenols can beused as anti-mildew agents, fungicides, fire retardant agents in variouspolyesters, monomers for the preparation of aromatic polycarbonates, andthe like.

The process of this invention can be made continuous and is based onusing quantitative amounts of reactants thereby enabling the extent ofhalogenation to be closely controlled. As a result, all of the halogenemployed is reacted with the diphenol so that there is realized not onlya savings in material and labor cost, but a savings in time as well asincreased product yield. Accordingly, the process of the invention canbe adapted for use with other processes to continuously produce suchmaterials as fire retardant polyesters, aromatic polycarbonates, and thelike.

Methylene chloride in the solvent system of the present invention isemployed in amounts sufficient to result in a clear solution when thehalogenation reaction is complete.

Use of sulfuryl chloride as the halogenating agent with such acidsensitive materials results in preventing or minimizing the deleteriouseffect of the hydrogen halide produced during the reaction which, inturn, can result in the formation of undesirable by-products. During thereaction, the sulfuryl chloride generates a gas, sulfur dioxide, in situwhich is neutral to the reaction and which serves to purge the reactionof the hydrogen halide coproduct before this coproduct can effect sidereactions. Thus, chlorinations using sulfuryl chloride are "selfsweeping" and result in producing products of high purity. The followingequation exemplifies the reaction of the process of the invention using,as the diphenol, bisphenol-A; i.e., 4,4'-isopropylidenediphenol (BPA):##STR3## Thus, the improvement over chlorination with elemental chlorineis readily recognizable by the formation of essentially colorlesssolutions and the absence of the characteristic, strong odor ofchlorophenols.

By minimizing the undesirable hydrogen halide coproduct, IIX, theformation of deleterious by-products, illustrated by the followinggeneral equation, are also minimized: ##STR4##

Accordingly, the halogenated diphenols produced using the process ofthis invention can be represented by the following general formula:##STR5## wherein Xm and Xn are chlorine, bromine, and mixtures thereofwith the proviso that either Xm or Xn is chlorine; Y is independentlyselected from the group consisting of C₁ -C₄ alkyl and hydrogen; m and nare each 0-2 with the proviso that m+n equal at least 0.1, but no morethan 2; and, W is a member selected from the following group:

(a) --CH₂ --_(r) wherein r is an integer of 0-10 with the proviso thatwhen both Xm and Xn are chlorine and m and n are each 1, r is 0 or 2-10;##STR6## wherein R is a member of the group consisting of C₁ -C₁₀ alkyland C₆ -C₁₄ aryl; ##STR7## wherein R and R' can each independently bethe same as R in (b) above; ##STR8## wherein p and q can eachindependently be 0-1; and,

(e) --O--

W and X are the same in the formulas for equations V as described forformula VI.

In producing the diphenol of formula VI wherein W can be (a), (b) or(c), particularly (c), the formation of deleterious by-products isespecially pronounced when employing prior art processes. When theprocess of this invention is employed, however, the formation of suchdeleterious by-products is dramatically minimized and virtuallyeliminated. Thus, the halogenated diphenols produced in accordance withthis invention are virtually colorless or white as compared to thediscolored halogenated diphenols obtained by prior art processes.

The temperature of the halogenation reaction can be about 0°-80° C., butis preferably held at about ambient temperature; i.e., 20°-35° C.

The amount of halogen added can vary depending upon the extent ofhalogenation desired. Thus, halogen can be added in amounts of about0.1-2 moles per mole of diphenol employed.

Since the reaction in the process of the invention is based uponquantitative consumption of halogen, the process enables the degree ofhalogenation of the diphenol to be closely controlled. Accordingly,predetermined statistical mixtures of unreacted diphenol and reacteddiphenol can be readily obtained. The amount of each obtained dependsupon the moles of halogen added.

As can be seen from the FIGURE, a statistical maximum of 50 mole percentof monohalodiphenol obtains at a mole ratio of halogen:diphenol of 1:1,whereas a statistical maximum of essentially 100 mole percentdihalodiphenol obtains at a mole ratio of halogen:diphenol of 2:1.Accordingly, it is possible to produce essentially 100% of puredihalodiphenol. Alternatively, statistic 1 ternary mixtures comprisingunreacted diphenol, monohalodiphenol and dihalodiphenol can be obtainedas shown by the FIGURE. This also pertains when mixtures of halogens areemployed.

Typical of some of the diphenols that can be employed in this inventionare bisphenol-A (2,2-bis(4-hydroxyphenyl)propane, also referred to as4,4'-isopropylidenediphenol), bis(4-hydroxyphenyl)methane,2,2-bis(4-hydroxy-3-methylphenyl)propane,4,4-bis(4-hydroxyphenyl)heptane, 1,1-bis(4-hydroxyphenyl)ethane,3-methyl-2,2-bis(4-hydroxyphenyl)propane, bis-(4-hydroxyphenyl)sulfone,bis-(4-hydroxyphenyl)ether, and the like. Other non-halogenateddiphenols of the bisphenol type can also be used such as are disclosedin U.S. Pat. Nos. 2,999,835, 3,028,365 and 3,334,154.

PREFERRED EMBODIMENT OF THE INVENTION

The following examples are set forth to more fully and clearlyillustrate the present invention and are intended to be, and should beconstrued as being, exemplary and not limitative of the invention.Unless otherwise stated, all parts and percentages are by weight.

EXAMPLE 1

To a slurry of 684 g (3.0 moles) of 4,4'-isopropylidenediphenol, (BPA)in 2000 ml of methylene chloride was added, dropwise at ambienttemperature, 810 g (6.0 moles) of sulfuryl chloride. Copious evolutionof hydrogen chloride and sulfur dioxide soon ensued, accompanied bygradual warning of the slurry to 35° C. and refluxing of the solvent.The addition of sulfuryl chloride required about 6 hours, by which thetime most of the BPA became dissolved. After one hour of refluxing bythe application of external heat, the clear solution was sampled for gaschromatographic analysis. (6'×1/8" stainless steel, 5% Silicon OV-101 onAnakrom ABS (acrylonitrile-butadiene-styrene) column, 8°-330° C. range,programmed at 80° C./minute). This indicated by matching, aftertrimethylsilylation with bis(trimethylsilyl)trifluoroacidamide, thecorrect retention times of authentic reference samples, the followingcomposition:

    ______________________________________                                                                    Compo-                                                                Retention                                                                             sition                                                                Time (min.)                                                                           (mole %)                                          ______________________________________                                        4,4'-isopropylidenediphenol                                                                         17.1      0.9                                           2-chloro-4,4'-isopropylidenediphenol                                                                18.3      7.5                                           2,2'-dichloro-4,4'-isopropylidenediphenol                                                           19.8      93.6                                          2,2',6-trichloro-4,4'-isopropylidenediphenol                                                        20.8      1.0                                           2,2',6,6'-tetrachloro-4,4'-                                                   isopropylidenediphenol                                                                              22.6      0.0                                           Reference (p-cumylphenol)                                                                           13.0                                                    ______________________________________                                    

To increase the dihalodiphenol content of the preparation and replacethe sulfuryl chloride that had been swept out of the system by theevolving gases, 27.8 g (0.28 mole) of sulfuryl chloride was added within30 minutes to the original solution, which then was heated to reflux for3 hours and sampled for an additional gas chromatographic analysis,which showed the following composition:

    ______________________________________                                                                 Composition                                          Composition              (mole %)                                             ______________________________________                                        4,4'-isopropylidenediphenol                                                                            0.4                                                  2-chloro-4,4'-isopropylidenediphenol                                                                   3.2                                                  2,2'-dichloro-4,4'-isopropylidenediphenol                                                              96.0                                                 2,2',6-trichloro-4,4'-isopropylidenediphenol                                                           1.2                                                  2,2',6,6'-tetrachloro-4,4'-isopropylidenediphenol                                                      0.0                                                  ______________________________________                                    

The solution was added to 3 liters of water, stirred and the crystalsthat formed were filtered through a sintered glass suction funnel,rinsed twice with water and air dried. The pure white crystals of2,2'-dichloro-4,4'-isopropylidenediphenol trihydrate were obtained in1053 g or essentially quantitative yield and showed a 97.2% assay inthis compound. The high purity was also confirmed by its melting pointof 90.5°-92.0° C. Infrared, ultraviolet, proton and ¹³ C-nmr alsoconfirmed both the purity and the structure of the product.

EXAMPLE 2

The procedure of Example 1 was repeated, except that only half as muchsulfuryl chloride (3.0 moles) but twice as much methylene chloride wereused. Gas chromatographic analysis of the reaction sample, after theaddition of the chlorinating agent and one hour reflux, indicated thefollowing composition:

    ______________________________________                                                                 Composition                                          Compound                 (mole %)                                             ______________________________________                                        4,4'-isopropylidenediphenol                                                                            27.2                                                 2-chloro-4,4'-isopropylidenediphenol                                                                   49.0                                                 2,2'-dichloro-4,4'-isopropylidenediphenol                                                              23.7                                                 2,2',6-trichloro-4,4'-isopropylidenediphenol                                                           0.1                                                  ______________________________________                                    

This composition thus corresponded very closely to the theoretical,ideally random statistical distribution, which is 25:50:25%, unreactedBPA:monochloro BPA:dichloro BPA. Gas chromatographic analysis indicatedthe essential absence of by-products and that the original reactionmixture which, on water treatment, yielded colorless crystals, could bedirectly utilized for the preparation of a corresponding statisticalmixture of polycarbonates.

Furthermore, the statistical composition that was maximized to themonochloro compound, could be worked up, if so desired, by selectiverecrystallization and the pure 2-chloro-4,4'-isopropylidenediphenol canbe isolated in high purity with a melting point of 105.5°-107° C.

By contrast, an analogous statistical mixture obtained by directchlorination, as shown in Example 3 below, yielded a pink or redishreaction mixture that had to be extensively purified by treatment withalkali and/or recrystallization, thus destroying the statisticallyrandom composition before it could be utilized for the preparation ofpolycarbonates of acceptable purity and reproducible composition.

EXAMPLE 3

The procedure of Example 2 was repeated, except that the chlorinationwas carried out with an equivalent amount of elemental chlorine (3.0moles) instead of sulfuryl chloride. As the chlorination progressed, thesolution turned gradually pink then deep red and, concomitantly, thecharacteristic odor of chlorophenols gradually developed. As thereaction mixture was sampled for chromatographic analyses, the formationof significant amounts of by-products as the chlorination was finishedwas confirmed by the presence of 0.1-1.2% chlorophenols and higherboiling impurities which preceded the emergence of chloro-BPA's.

EXAMPLE 4

To a solution of 134.2 g (0.5 mole) of 4,4'-cyclohexylidenediphenol in1900 ml of refluxing benzene was added gradually 135.0 g (1.0 mole) ofsulfuryl chloride in the course of 5 hours. After an additional one hourof reflux, the yellow solution was sampled for gas chromatographicanalysis, which indicated the following composition:

    ______________________________________                                                        Retention                                                                              Composition                                                          Time (min.)                                                                            (mole %)                                             ______________________________________                                        4,4'-cyclohexylidenediphenol                                                                    19.57      0.0                                              2-chloro-4,4'-                                                                cyclohexylidenediphenol                                                                         20.82      10.3                                             2,2'-dichloro-4,4'-                                                           cyclohexylidenediphenol                                                                         23.15      89.7                                             Reference (4-cumylphenol)                                                                       12.36                                                       ______________________________________                                    

Workup by treatment with water, filtration and rinsing yielded 161.5 gof white crystals which, after recrystallization from methylenechloride, contained 98.9% di-, 0.4% mono- and 0.7%trichloro-4,4'-cyclohexylidenediphenol and had a melting point of143°-145° C.

EXAMPLE 5

The procedure of Example 3 was repeated, except that only 81.0 g (0.6mole) of sulfuryl chloride was employed. Gas chromatographic analysis atthe end of the reaction indicated a nearly random statisticaldistribution:

    ______________________________________                                                                Composition                                           Compound                (mole %)                                              ______________________________________                                        4,4'-cyclohexylidenediphenol                                                                          16.0                                                  2-chloro-4,4'-cyclohexylidenediphenol                                                                 47.2                                                  2,2'-dichloro-4,4'-cyclohexylidenediphenol                                                            36.8                                                  ______________________________________                                    

EXAMPLE 6

The procedure of Example 1 was repeated on the one molar scale by using214.3 g (1.0 mole) of 4,4'-ethylidenediphenol, 1 L of methylene chlorideand 270.0 g (2.0 moles) of sulfuryl chloride. Gas chromatographyindicated the following composition:

    ______________________________________                                                         Retention                                                                              Composition                                                          Time (min.)                                                                            (mole %)                                            ______________________________________                                        4,4'-ethylidenediphenol                                                                          19.87      0.1                                             2-chloro-1,4'-ethylidenediphenol                                                                 21.21      17.0                                            2,2'-dichloro-4,4'-                                                           ethylidenediphenol 22.68      82.2                                            2,2',6-trichloro-4,4'-                                                        ethylidenediphenol 23.02      0.2                                             Reference (p-cumylphenol)                                                                        16.43                                                      ______________________________________                                    

EXAMPLE 7

The procedure of Example 1 was repeated except that a slurry of 196.2 g(0.668 m) of 4,4'-(2,2,2-trichloroethylidene) in 300 ml of methylenechloride was chlorinated with 183 g (1.356 mole) of sulfuryl chloridebetween 21° and 36° C. Workup of the reaction mixture by filtering offundissolved starting material (75.9 g cr 0.26 mole) yielded 165.3 g of alight brown oil with the following composition:

    ______________________________________                                                                        Compo-                                                             Retention  sition                                        Compound             Time (min.)                                                                              (mole %)                                      ______________________________________                                        4,4'-(2,2,2-trichloroethylidene)diphenol                                                           20.02      0.1                                           2-chloro-4,4'-(2,2,2-                                                         trichloroethylidene)diphenol                                                                       11.14      0.6                                           2,2'-dichloro-4,4'-(2,2,2-                                                    trichloroethylidene)diphenol                                                                       22.03      50.7                                          2,2',6-trichloro-4,4'-(2,2,2-                                                 trichloroethylidene)diphenol                                                                       22.97      46.0                                          2,2',6,6'-tetrachloro-4,4'-(2,2,2-                                            trichloroethylidene)diphenol                                                                       23.84      2.6                                           Reference (p-cumylphenol)                                                                          12.58                                                    ______________________________________                                    

EXAMPLE 8

The procedure of Example 1 was repeated except that to a slurry of 50.0g (0.178 mole) of 4,4'-(dichlorovinylidene)diphenol in 3 L of methylenechloride was added 50.0 g (0.37 mole) of sulfuryl chloride in the courseof one hour, at which time all of the diphenol was in solution. Therefluxing of the solution was continued by the application of externalheat until gas evolution ceased. Workup of the reaction mixture, asdescribed in Example 1, yielded white crystals, for which gaschromatography indicated the following composition:

    ______________________________________                                                                       Compo-                                                            Retention   sition                                         Compound           Time (min.) (mole %)                                       ______________________________________                                        4,4'-(dichlorovinylidene)diphenol                                                                18.97       0.2                                            2-chloro-4,4'-                                                                (dichlorovinylidene)diphenol                                                                     20.11       18.5                                           2,2'-dichloro-4,4'-                                                           (dichlorovinylidene)diphenol                                                                     20.91       81.1                                           2,2',6-trichloro-4,4'-                                                        (dichlorovinylidene)diphenol                                                                     21.91       0.2                                            2,2',6,6'-tetrachloro-4,4'-                                                   (dichlorovinylidene)diphenol                                                                     22.87       0.0                                            Reference (p-cumylphenol)                                                                        12.36                                                      ______________________________________                                    

Recrystallization of the white solids from hexane yielded colorlesscrystals of the 2,2'-dichloro-4,4'-(dichlorovinyldene)diphenol, mp.109°-110.5° C., and an assay of 98.0%.

EXAMPLE 9

The procedure of Example 1 was repeated, except that a slurry of 50.5 g(0.25 mole) of 4,4'-oxydiphenol in 3 L of methylene chloride waschlorinated with 68.0 g (0.5 mole) of sulfuryl chloride. After theevolution of gases ceased, the colorless solution was sampled for gaschromatographic analysis which showed the following composition:

    ______________________________________                                                           Retention  Composition                                     Compound           Time (min.)                                                                              (mole %)                                        ______________________________________                                        4,4'-oxydiphenol   18.15      0.0                                             2,2'-dichloro-4,4'-oxydiphenol                                                                   20.97      94.0                                            2,2',6-trichloro-4,4'-oxydiphenol                                                                22.23      6.0                                             ______________________________________                                    

Recrystallization of the white solids from methylene chloride yieldedcolorless crystals of 2,2'-dichloro-4,4'-oxydiphenol, mp 113°-114° C.,which were 98.1% pure by gas chromatography.

EXAMPLE 10

The procedure of Example 1 was repeated, except that a thin slurry of296 g (1.0 mole) of 2,2'-dimethyl-4,4'-cyclohexylidenediphenol in 10 Lof methylene chloride was chlorinated with 270 g (2.0 moles) of sulfurylchloride in the course of 4 hours. Gas chromatographic analysisindicated the following composition:

    ______________________________________                                                           Retention  Composi-                                        Compound           Time (min.)                                                                              tion (%)                                        ______________________________________                                        2,2'-dimethyl-4,4'-                                                           cyclohexylidenediphenol                                                                          22.72      8.6                                             6-chloro-2,2'-dimethyl-4,4'-                                                  cyclohexylidenediphenol                                                                          24.01      7.1                                             6,6'-dichloro-2,2'-dimethyl-4,4'-                                             cyclohexylidenephenol                                                                            25.44      84.3                                            ______________________________________                                    

The structures of the new compounds described above were confirmed byproton nmr analyses, which yielded correct integrated areas for thealiphatic and aromatic protons and the absence of chloromethylatedderivatives. The pure product,2,2'-dichloro-4,4'-cyclohexylidenedi-o-cresol, was obtained in 98.8%purity with a 136.5°-137.5° C. mp after recrystallization from thewater-methanol mixture.

As mentioned earlier, the process disclosed in German Pat. No. P25 20317.2 results in producing a mixture of unreacted bisphenol andstatistical mixtures of halogenated bisphenol whereas the process ofthis invention, as shown by the foregoing examples, results in producingtrue statistical mixtures comprising unreacted bisphenol,monohalobisphenol and dihalobisphenol.

What is claimed is:
 1. A halogenated diphenol mixture having asignificantly reduced quantity of trihalo substituted and tetrahalosubstituted diphenol, said mixture containing predetermined, statisticalquanities of unreacted diphenol, monohalodiphenol and dihalodiphenol,said halogenated diphenol being represented by the general formula##STR9## wherein Xm and Xn are chlorine, bromine and mixtures thereofwith the proviso that either Xm or Xn is chlorine; Y is independentlyselected from the group consisting of C₁ -C₄ alkyl and hydrogen; m and nare each 0-2 with the proviso that m+n equal at least 0.1, but no morethan 2.0; and, W is --O--.
 2. The halogenated diphenol of claim 1wherein Y is hydrogen.
 3. The halogenated diphenol of claim 1 wherein Yis CH₃.
 4. The halogenated diphenol of claim 1 wherein Xm and Xn areeach chlorine and m+n equal 2.0.
 5. The halogenated diphenol of claim 1wherein Xm is chlorine, Xn is bromine and m+n equal 2.0.
 6. Thehalogenated diphenol of claim 4 wherein Y is hydrogen.
 7. Thehalogenated diphenol of claim 4 wherein Y is CH₃.